1. Technical Field
The present disclosure relates to a grip width adjusting mechanism which adjusts a grip width that is a distance between a pair of grips grasping a packaging bag while suspending the packaging bag according to work contents of each step in a successive packaging process executed by a packaging machine.
2. Related Art
A grip unit having a pair of grips gasping a side edge of a packaging bag has conventionally been configured to be capable of adjusting a distance (hereinafter, “grip width”) between the paired grips in a successive packaging process executed by a packaging machine according to a bag width of a packaging bag to be treated.
Japanese Patent Application Publication No. JP-A-2005-119727 discloses a grip pair opening adjusting device in a packaging machine. When a handle is operated to rotationally move an adjusting lever in a forward direction, a holder linked to the adjusting device is rotated outward about a support pin, whereby the grip pair is opened. When the adjusting lever is rotationally moved in a reverse direction, the holder is rotated inward, whereby the grip pair is closed.
However, the opening adjusting device and the grip unit paired with the opening adjusting device are linked to each other. More specifically, when 4 to 16 grip units are provided on a rotating body in a radial arrangement, for example, the adjusting devices whose number is the same as that of the grip units are required.
Accordingly, firstly, when the grip width is initially set according to the bag width of the packaging bag to be treated, the initial setting needs to be executed for every grip unit individually. As a result, there is a possibility that an actual value adjusted for every grip unit would vary relative to the initially set value of grip width.
Secondly, in a feeding step where packaging bags are fed to the packaging step, a filling step where the packaging bags are filled with an article and a sealing step where the packaging bags are sealed, the grip width is adjusted according to each step in order that a funnel or the like may smoothly be inserted into a bag mouth and/or rucks may be prevented from being produced on a part of the packaging bag near the bag mouth. In this case, when the initial set value varies as described above, there is a possibility that the variations enlarge and spread in the successive packaging process. Furthermore, when an electric motor is installed for every adjusting device so that the grip width may be continuously be changed automatically, the adjusting devices and motors need to be individually controlled according to each step of the packaging process. Since a plurality of motors is provided, there is a possibility that a synchronous control and wiring of the motors require a complicate configuration. Since the motors consume electrical power, there is a possibility that large load is applied to the environment.